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<head>
  <meta charset="UTF-8"></meta>
  <title>Title</title>
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<body>
<ul>
    <li id="l1" class="c1">北京</li>
    <li id="l2">上海</li>
    <li id="c3">神州</li>
    <li id="c4">武汉</li>

</ul>
</body>
</html>